Building truss

ABSTRACT

A truss for a roof of a building structure includes a lower span having first and second horizontal joist portions on opposite ends of the truss. The first and second joist portions are adapted to be placed on upper ends of first and second sidewalls of a structure and with the first and second joist portions extending toward one another in substantially linear alignment. The first and second joist portions have a combined length less than a distance between the sidewalls. At least a third joist portion is disposed between opposing ends of the first and second joist portions and beneath a plane defined by the first and second joint portions. The third joist portion extends parallel to and spaced from the first and second joist portions. A first bracing member connects a first end of the third joist portion to a first joist portion. A second bracing member connects a second end of a third joist portion to the second joist portion. A plurality of rafters are connected to the lower span and connect at an angle thereto to define a ridge above the third joist portion. A plurality of braces connect the joist portions and the rafters in a pattern leaving a substantially unobstructed area above the third joist portion.

I. BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains to trusses for fabricating the roof of a building. More particularly, this invention pertains to a truss to provide enhanced storage beneath the roof of a structure.

2. Description of the Prior Art

Trusses are well known in the construction trade. A truss is a prefabricated structure to be used in forming the roof of a building. Commonly, a truss includes ceiling joist which is a horizontal member having a length sufficient for ends of the joist to bear on opposing walls of a structure. Rafters extend up from the opposite ends of the joist and terminate at a ridge line usually above the center line of the joint. A trust will also include a plurality of bracing members which brace the members to the joists and which are fastened in place by metal braces.

Not uncommonly, trusses are designed to have a central area which is generally unobstructed so that when a roof structure is completed, the unobstructed areas of the trusses are aligned to create an unobstructed volume which can be used either as an additional room or for storage space. Such storage space trusses are particularly useful above a garage to provide additional storage space for seasonal items. Unfortunately, not all trusses can provide adequate storage space. For example, the amount of the height of the storage area as well as its volume are highly dependent upon factors such as the span of the joist and the pitch of the roof. It is an object of the present invention to provide a truss for such limited environments which provides an enhanced headroom within the storage area.

II. SUMMARY OF THE INVENTION

According to the preferred embodiment of the present invention a truss is disclosed for a roof of a building structure where the structure has opposing first and second sidewalls terminating in an upward elevation. The truss includes a lower span. The lower span has first and second horizontal joist portions on opposite ends of the truss. The first and second joist portions are adapted to be placed on upper ends of the first and second sidewalls and with the first and second joist portions extending toward one another in substantially linear alignment. The first and second joist portions have a combined length less than a distance between the sidewalls. At least a third joist portion is disposed between opposing ends of the first and second joist portions and beneath a plane defined by the first and second joint portions. The third joist portion extends parallel to and spaced from the first and second joist portions. A first bracing member connects a first end of the third joist portion to a first joist portion. A second bracing member connects a second end of a third joist portion to the second joist portion. A plurality of rafters are connected to the lower span and connect at an angle thereto to define a ridge above the third joist portion. A plurality of braces connect the joist portions and the rafters in a pattern leaving a substantially unobstructed area above the third joist portion.

III. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation view of a prior art truss showing an unobstructed area beneath a ridge of the truss;

FIG. 2 is the view of FIG. 1 showing a person within the unobstructed area but constrained to stand at less than full height within the unobstructed area;

FIG. 3 is a structure with a roof formed from the trusses of FIG. 1;

FIG. 4 is a front elevation view of a truss according to the present invention;

FIG. 5 is the view of FIG. 4 showing a person able to stand at full height within the unobstructed area of the truss of FIG. 4; and

FIG. 6 is a structure with a roof fabricated with trusses according to the present invention.

IV. DESCRIPTION OF THE PREFERRED EMBODIMENT

With initial reference to FIGS. 1 through 3, a prior art truss 10 is shown with placement on a structure such as a garage 12 in FIG. 3. The garage 12 includes sidewalls 14 and 16 which terminate at upper elevation 15 and 17. In proper construction, the upper elevations 15 and 17 are aligned so that a true horizontal line stands between the upper ends 15 and 17.

The roof of the structure 12 is formed by a plurality of trusses 10 aligned in parallel alignment and sheathed with a roofing material 18 to provide weather-tight sealing of the roof. The trusses 10 are conventional prior art trusses designed to create a storage space. The truss includes a unitary joist 20 having a length L equal to or greater than the distance between the sidewalls 14, 16 of the structure.

Rafters 22 and 24 extend from the ends of the joist 20 extend upwardly at an angle to meet at a ridge point 26 which, in the example shown, resides substantially above the center of the joist 20. A plurality of vertical braces 28 through 31 extend between the rafters and the joists 20. Also angular braces 32, 33 extend from the joist 20 at the intersection of the rafter 22, 24 with the braces 28, 31 to create a triangulation for force distribution. A ceiling joist brace 34 extends between the vertical trusses 29, 30 beneath the ridge 26.

The intersection of all members (i.e., rafters, braces and joists) are connected by metal plates 50 covering both intersecting members and including fasteners such as nails to complete the joinder of the members at the intersection.

It will be noted there are no angular or other rafters within the area 36 defined by braces 29, 30, 34 and joist 20. Accordingly, this area is an unobstructed area such that when a plurality of trusses are placed in parallel alignment on a structure as shown in FIG. 3, the unobstructed area 36 combines to create an unobstructed volume which may be used for storage, occupation or the like.

The amount of headroom (i.e., the distance between joist 34 and joist 20) varies with the length of the span of the joist 20 as well as the pitch of the rafters 22, 24. Pitch is the ratio of a unit height divided by the unit run (length of the rafter).

For roofs with very low pitch or a short span L, the amount of headroom can be quite small such that an occupant cannot stand within the space as illustrated in FIGS. 2 and 3 with the silhouette of a human H crouching in response to the restricted headroom.

In certain construction sites, the height of a garage roof (i.e., from the floor of the garage to the rafters and joist 20) can be substantially greater than is necessary for vehicle storage and other uses. As a result, there is a substantial amount of wasted headroom within many garages due to grading and other factors at the construction site.

The present invention is directed to a truss which is particularly applicable for such situations which can increase the amount of headroom within a storage space but without altering the length or pitch of any truss. Such a truss is shown in FIGS. 4 and 5 and combined to form a completed roof in FIG. 6.

In FIG. 4, the truss 100 includes a lower span 102. The lower span includes a first horizontal member or joist portion 104 and a second horizontal joist portion 106. The first and second joist portions 104, 106 are adopted to be placed on upper ends 15, 17 of the first and second sidewalls 14, 16 of a structure 12 with the first and second joist portions 104, 106 extending toward one another in substantially linear alignment.

The first and second joist portions 104, 106 have a combined length L₁ plus L₂ which is less than a length L between the sidewall 14, 16 of the structure 12. A third joist portion 108 (substantially the same length as header joist 134) is positioned between the opposing ends of the first and second joist portions 104, 106 and beneath a plane defined by the first and second joist portions while extending parallel to and spaced from the first and second joist portions 104, 106.

A first bracing member 110 connects a first end of the third joist portion to the first joist portion 102. A second bracing member 112 connects a first end of the third joist portion 108 to the second joist portion 106.

Rafters 122, 124 extend up from the ends of the first and second joist portions 102, 106 to meet to define a ridge point 126 above a third joist portion 108. A plurality of braces including vertical braces 128, 129, 130 and 131 extend between the joist portions 104, 108 and 106 to the rafters 122, 124.

Triangular or angled braces 133 extend from the first and second joist portions to the intersection of the rafters 122, 124 and the vertical braces 128, 131 to create a triangulation for distribution of forces. It will be noted that the vertical rafters 129, 130 connect with both the first joist portion and the intermediate joist portion while the vertical brace 130 connects with the third joist portion and the second joist portion 106.

A horizontal brace 134 extends between the vertical braces 129, 130. The distance between the horizontal brace 134 and the third joist portion 108 defines a headroom and an unobstructed area 136. As shown in FIG. 5, by lowering a portion of the lower span by the addition of the third joist portion 108, the headroom can substantially be increased to permit a person to stand in a full upright position within the unobstructed area 136 and without the need to alter either the total span of the truss or the pitch of the truss.

While headroom in the garage itself is sacrificed to accommodate this increase in headroom in the truss, many garages today are being built with substantially excess headroom due to grading constraints and other factors. When the trusses 100 of the present invention are aligned in a common roof as shown in FIG. 6, a substantial volume can be added above a garage or other structure for storage, occupation or the like without the need to alter the aesthetic benefits of a particular truss span and pitch.

It has been shown how the objects of the present invention have been attained in the preferred embodiment. Modification and equivalents of the disclosed concepts are intended to be included within the scope of the appended claims.

The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. 

1. A truss for a roof of a building structure having opposing first and second sidewalls terminating at an upper elevation, said truss comprising: a lower span including: first and second horizontal joist portions on opposite ends of said truss with said first and second joist portions adapted to be placed on upper ends of said first and second sidewalls and with said first and second joist portions extending toward one another in substantially linear alignment; said first and second joist portions have a combined length less than a distance between said sidewalls; at least a third joist portion disposed between opposing ends of said first and second joist portions and beneath a plane defined by said first and second joist portions and extending parallel to and spaced from said first and second joist portions; a first bracing member connecting a first end of said third joist portion to said first joist portion; a second bracing member connecting a second end of said third joist portion to said second joist portion; a plurality of rafters connected to said lower span and connected at an angle thereto to define a ridge above said third joist portion; a plurality of braces connecting said joist portions and said rafters in a pattern leaving a substantially unobstructed area above said third joist portion.
 2. A truss according to claim 1 comprising a cross member between said braces and rafters above said third joist member and spaced therefrom to define an unobstructed area.
 3. A truss according to claim 1 wherein said rafters and joist portions define a truss plane.
 4. A roof comprising: a. a plurality of trusses having: i. a lower span including:
 1. first and second horizontal joist portions on opposite ends of said truss with said first and second joist portions adapted to be placed on upper ends of said first and second sidewalls and with said first and second joist portions extending toward one another in substantially linear alignment;
 2. said first and second joist portions have a combined length less than a distance between said sidewalls;
 3. at least a third joist portion disposed between opposing ends of said first and second joist portions and beneath a plane defined by said first and second joist portions and extending parallel to and spaced from said first and second joist portions;
 4. a first bracing member connecting a first end of said third joist portion to said first joist member;
 5. a second bracing member connecting a second end of said third joist portion to said second joist member; ii. a plurality of rafters connected to said lower span and connected at an angle thereto to define a ridge above said third joist portion; iii. a plurality of braces connecting said joist portions and said rafters in a pattern leaving a substantially unobstructed area above said third joist member; b. said trusses disposed in parallel alignment with said unobstructed areas of said trusses defining an unobstructed volume. 